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https://github.com/edk2-porting/linux-next.git
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ba73d98745
The may_follow_link(), may_linkat(), may_lookup(), may_open(), may_o_create(), may_create_in_sticky(), may_delete(), and may_create() helpers determine whether the caller is privileged enough to perform the associated operations. Let them handle idmapped mounts by mapping the inode or fsids according to the mount's user namespace. Afterwards the checks are identical to non-idmapped inodes. The patch takes care to retrieve the mount's user namespace right before performing permission checks and passing it down into the fileystem so the user namespace can't change in between by someone idmapping a mount that is currently not idmapped. If the initial user namespace is passed nothing changes so non-idmapped mounts will see identical behavior as before. Link: https://lore.kernel.org/r/20210121131959.646623-13-christian.brauner@ubuntu.com Cc: Christoph Hellwig <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: James Morris <jamorris@linux.microsoft.com> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
196 lines
5.2 KiB
C
196 lines
5.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/* fs/ internal definitions
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*
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* Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*/
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struct super_block;
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struct file_system_type;
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struct iomap;
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struct iomap_ops;
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struct linux_binprm;
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struct path;
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struct mount;
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struct shrink_control;
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struct fs_context;
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struct user_namespace;
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/*
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* block_dev.c
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*/
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#ifdef CONFIG_BLOCK
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extern void __init bdev_cache_init(void);
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extern int __sync_blockdev(struct block_device *bdev, int wait);
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void iterate_bdevs(void (*)(struct block_device *, void *), void *);
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void emergency_thaw_bdev(struct super_block *sb);
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#else
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static inline void bdev_cache_init(void)
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{
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}
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static inline int __sync_blockdev(struct block_device *bdev, int wait)
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{
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return 0;
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}
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static inline void iterate_bdevs(void (*f)(struct block_device *, void *),
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void *arg)
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{
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}
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static inline int emergency_thaw_bdev(struct super_block *sb)
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{
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return 0;
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}
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#endif /* CONFIG_BLOCK */
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/*
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* buffer.c
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*/
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extern int __block_write_begin_int(struct page *page, loff_t pos, unsigned len,
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get_block_t *get_block, struct iomap *iomap);
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/*
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* char_dev.c
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*/
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extern void __init chrdev_init(void);
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/*
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* fs_context.c
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*/
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extern const struct fs_context_operations legacy_fs_context_ops;
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extern int parse_monolithic_mount_data(struct fs_context *, void *);
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extern void fc_drop_locked(struct fs_context *);
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extern void vfs_clean_context(struct fs_context *fc);
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extern int finish_clean_context(struct fs_context *fc);
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/*
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* namei.c
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*/
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extern int filename_lookup(int dfd, struct filename *name, unsigned flags,
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struct path *path, struct path *root);
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extern int vfs_path_lookup(struct dentry *, struct vfsmount *,
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const char *, unsigned int, struct path *);
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long do_rmdir(int dfd, struct filename *name);
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long do_unlinkat(int dfd, struct filename *name);
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int may_linkat(struct user_namespace *mnt_userns, struct path *link);
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int do_renameat2(int olddfd, struct filename *oldname, int newdfd,
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struct filename *newname, unsigned int flags);
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/*
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* namespace.c
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*/
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extern struct vfsmount *lookup_mnt(const struct path *);
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extern int finish_automount(struct vfsmount *, struct path *);
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extern int sb_prepare_remount_readonly(struct super_block *);
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extern void __init mnt_init(void);
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extern int __mnt_want_write_file(struct file *);
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extern void __mnt_drop_write_file(struct file *);
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extern void dissolve_on_fput(struct vfsmount *);
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int path_mount(const char *dev_name, struct path *path,
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const char *type_page, unsigned long flags, void *data_page);
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int path_umount(struct path *path, int flags);
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/*
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* fs_struct.c
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*/
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extern void chroot_fs_refs(const struct path *, const struct path *);
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/*
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* file_table.c
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*/
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extern struct file *alloc_empty_file(int, const struct cred *);
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extern struct file *alloc_empty_file_noaccount(int, const struct cred *);
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/*
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* super.c
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*/
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extern int reconfigure_super(struct fs_context *);
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extern bool trylock_super(struct super_block *sb);
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struct super_block *user_get_super(dev_t, bool excl);
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void put_super(struct super_block *sb);
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extern bool mount_capable(struct fs_context *);
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/*
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* open.c
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*/
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struct open_flags {
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int open_flag;
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umode_t mode;
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int acc_mode;
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int intent;
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int lookup_flags;
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};
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extern struct file *do_filp_open(int dfd, struct filename *pathname,
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const struct open_flags *op);
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extern struct file *do_file_open_root(struct dentry *, struct vfsmount *,
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const char *, const struct open_flags *);
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extern struct open_how build_open_how(int flags, umode_t mode);
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extern int build_open_flags(const struct open_how *how, struct open_flags *op);
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long do_sys_ftruncate(unsigned int fd, loff_t length, int small);
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int chmod_common(const struct path *path, umode_t mode);
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int do_fchownat(int dfd, const char __user *filename, uid_t user, gid_t group,
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int flag);
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int chown_common(const struct path *path, uid_t user, gid_t group);
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extern int vfs_open(const struct path *, struct file *);
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/*
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* inode.c
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*/
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extern long prune_icache_sb(struct super_block *sb, struct shrink_control *sc);
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extern void inode_add_lru(struct inode *inode);
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extern int dentry_needs_remove_privs(struct dentry *dentry);
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/*
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* fs-writeback.c
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*/
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extern long get_nr_dirty_inodes(void);
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extern int invalidate_inodes(struct super_block *, bool);
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/*
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* dcache.c
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*/
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extern int d_set_mounted(struct dentry *dentry);
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extern long prune_dcache_sb(struct super_block *sb, struct shrink_control *sc);
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extern struct dentry *d_alloc_cursor(struct dentry *);
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extern struct dentry * d_alloc_pseudo(struct super_block *, const struct qstr *);
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extern char *simple_dname(struct dentry *, char *, int);
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extern void dput_to_list(struct dentry *, struct list_head *);
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extern void shrink_dentry_list(struct list_head *);
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/*
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* read_write.c
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*/
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extern int rw_verify_area(int, struct file *, const loff_t *, size_t);
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/*
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* pipe.c
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*/
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extern const struct file_operations pipefifo_fops;
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/*
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* fs_pin.c
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*/
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extern void group_pin_kill(struct hlist_head *p);
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extern void mnt_pin_kill(struct mount *m);
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/*
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* fs/nsfs.c
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*/
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extern const struct dentry_operations ns_dentry_operations;
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/* direct-io.c: */
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int sb_init_dio_done_wq(struct super_block *sb);
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/*
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* fs/stat.c:
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*/
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int do_statx(int dfd, const char __user *filename, unsigned flags,
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unsigned int mask, struct statx __user *buffer);
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